A roller assembly

Abstract

This invention discloses a roller assembly coupled to a housing for wafer cleaning. The roller assembly includes a movable wheel, a rotating shaft, a mounting base, and a sealing assembly. The sealing assembly is fixed to both the mounting base and the housing to seal the gap between them. The sealing assembly includes a sealing gasket, an outer pressure ring, and an inner pressure ring. The inner pressure ring fixes the sealing gasket to the mounting base, and the outer pressure ring fixes the sealing gasket to the housing. The inner pressure ring is located inside the outer pressure ring.

Description

Technical Field

[0001] This invention relates to the field of semiconductor wafer cleaning technology, and more particularly to a roller assembly. Background Technology

[0002] In the semiconductor industry, the cleanliness of the wafer surface is one of the most important factors affecting the reliability of semiconductor devices. During wafer fabrication processes such as deposition, plasma etching, photolithography, and electroplating, contaminants and / or particles can be introduced onto the wafer surface, leading to a decrease in surface cleanliness and a low yield of the manufactured semiconductor devices. Therefore, multiple surface cleaning processes are required during wafer manufacturing to remove contaminants such as metal ions, atoms, organic matter, and particulate matter adhering to the wafer surface.

[0003] The brushing module used for cleaning wafers is equipped with rollers that drive the wafer to rotate or rollers that follow the wafer to rotate. The rollers are in direct contact with the wafer. In actual production, it has been found that the edges of the wafers are difficult to clean. Even after brushing, contaminants remain on the edges of the wafers and are difficult to remove completely. Summary of the Invention

[0004] This invention provides a roller assembly designed to at least address one of the technical problems existing in the prior art.

[0005] This invention provides a roller assembly coupled to a housing for wafer cleaning. The roller assembly includes a movable wheel, a rotating shaft, a mounting base, and a sealing assembly. The sealing assembly is fixed to both the mounting base and the housing to seal the gap between them. The sealing assembly includes a sealing gasket, an outer pressure ring, and an inner pressure ring. The inner pressure ring fixes the sealing gasket to the mounting base, and the outer pressure ring fixes the sealing gasket to the housing. The inner pressure ring is located inside the outer pressure ring.

[0006] In one embodiment, the upper part of the outer pressure ring has a water-blocking structure.

[0007] In one embodiment, the water-blocking structure includes a water-blocking eave extending outward from the outer peripheral edge of the outer pressure ring and a first groove formed between the water-blocking eave and the housing.

[0008] In one embodiment, the water-retaining eaves are crescent-shaped structures that gradually narrow from high to low.

[0009] In one embodiment, the lower part of the outer pressure ring has a drainage structure.

[0010] In one embodiment, the drainage structure is a notch at the bottom of the outer pressure ring.

[0011] In one embodiment, the inner circumferential surface of the outer pressure ring is provided with a first guide slope.

[0012] In one embodiment, the inner pressure ring has a water-guiding structure.

[0013] In one embodiment, the water guiding structure is a water guide eave that extends outward at an angle from the outer peripheral edge of the inner pressure ring toward the side of the movable wheel.

[0014] In one embodiment, the water guide is annular.

[0015] In one embodiment, the outer peripheral edge of the water guide is provided with a second guiding slope.

[0016] In one embodiment, the rotating shaft is rotatably disposed within the mounting base, and one end of the rotating shaft is connected to a movable wheel.

[0017] The beneficial effects of the embodiments of the present invention include: achieving the sealing function of the roller assembly and improving the sewage discharge capacity. Attached Figure Description

[0018] The advantages of the present invention will become clearer and easier to understand through the detailed description taken in conjunction with the following accompanying drawings, but these drawings are merely illustrative and do not limit the scope of protection of the present invention, wherein:

[0019] Figure 1 This invention illustrates a wafer cleaning apparatus according to an embodiment of the present invention;

[0020] Figure 2 This invention illustrates a roller assembly with the movable wheel removed, according to an embodiment of the present invention.

[0021] Figure 3 A cross-section of the roller assembly is shown. Detailed Implementation

[0022] The technical solutions of the present invention will be described in detail below with reference to specific embodiments and accompanying drawings. The embodiments described herein are specific implementations of the present invention, used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary, and should not be construed as limiting the implementation methods and scope of protection of the present invention. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. In addition to the embodiments described herein, those skilled in the art can employ other obvious technical solutions based on the content disclosed in the claims and specification of this application. These technical solutions include those that make any obvious substitutions and modifications to the embodiments described herein. It should be understood that, unless specifically stated otherwise, for ease of understanding, the following description of specific embodiments of the present invention is based on the premise that the relevant equipment, devices, components, etc., are in their original static state and are not given external control signals or driving forces.

[0023] Furthermore, it should be noted that the terms used in this application to indicate orientation, such as front, back, up, down, left, right, top, bottom, front, back, horizontal, and vertical, are merely for ease of explanation and to aid in the understanding of relative position or direction, and are not intended to limit the orientation of any device or structure.

[0024] To illustrate the technical solution described in this invention, the following description will be provided with reference to the accompanying drawings and embodiments.

[0025] In this application, chemical mechanical polishing is also called chemical mechanical planarization, and wafer is also called wafer, silicon wafer, substrate, etc., with the same meaning and actual function.

[0026] like Figure 1 As shown, an embodiment of the present invention provides a wafer cleaning device 1 for cleaning wafers w, including: a housing 11, a wafer support mechanism 12, two cleaning brushes 14, a cleaning brush drive mechanism 13, a liquid inlet mechanism 15, and a liquid supply component 16, etc.

[0027] like Figure 1 As shown, the interior of the enclosure 11 forms a process chamber, providing an environment for processing wafer w.

[0028] like Figure 1 As shown, two cleaning brushes 14 are respectively disposed on the front and rear sides of the wafer w and roll to clean the surface of the wafer w. The two cleaning brushes 14 roll in opposite directions. The two cleaning brushes 14 are designated as the first cleaning brush and the second cleaning brush, respectively disposed on the front and rear sides of the wafer w to be cleaned, and can roll around their own axes to contact and clean the surface of the wafer w. The cleaning brushes 14 have a cylindrical roller structure and are made of a material with good water absorption, such as polyvinyl alcohol (PVA).

[0029] like Figure 1 As shown, a liquid inlet mechanism 15 connected to one end of the cleaning brush 14 continuously supplies liquid to the cleaning brush 14, keeping the cleaning brush 14 moist. The cleaning brush 14 is made of a porous material capable of absorbing a large amount of liquid. This liquid can be an acidic or alkaline solution, or deionized water. The liquid inlet mechanism 15 is connected to the liquid inlet end of the cleaning brush 14, filling the cleaning brush 14 with liquid. After being filled with liquid, the cleaning brush 14 softens and can be used to brush the wafer w; therefore, it is necessary to keep the cleaning brush 14 in a liquid-filled state at all times during the cleaning process.

[0030] The cleaning brushes 14 located on both sides of the wafer w can move horizontally to move away from or towards the wafer w. When the cleaning brushes 14 move away from the wafer w, a certain gap is maintained between the cleaning brushes 14 and the wafer w, and the wafer handling robot can grip the wafer w to remove the cleaned wafer w; when the cleaning brushes 14 move towards the wafer w, the cleaning brushes 14 come into contact with the wafer w and perform cleaning on the surface of the wafer w in a contact manner.

[0031] like Figure 1 As shown, the cleaning brush drive mechanism 13 is used to drive two cleaning brushes 14 to move towards each other and clamp the wafer w at a certain angle for rolling cleaning. The cleaning brush drive mechanism 13 includes a cleaning brush rotation drive module and a cleaning brush horizontal drive module.

[0032] The cleaning brush rotation drive module is used to support two cleaning brushes 14 located on both sides of the wafer w to be cleaned, and to drive the cleaning brushes 14 to rotate.

[0033] A horizontal drive module for the cleaning brush is connected to a rotary drive module for the cleaning brush, driving the rotary drive module and the cleaning brush 14 thereon to move as a whole. The horizontal drive module may include a guide rail, a lead screw, and a drive component. The guide rail and lead screw are respectively connected to the rotary drive module so that the rotary drive module moves along the guide rail under the drive of the lead screw. The drive component is located at the end of the lead screw and drives the lead screw to move, thereby moving the cleaning brush support assembly and the cleaning brush 14 as a whole, so that both ends of the cleaning brush 14 simultaneously contact or move away from the wafer w. Furthermore, lead screws are respectively provided at both ends of the cleaning brush 14, allowing for independent adjustment of the movement distance at each end of the cleaning brush 14.

[0034] like Figure 1 As shown, the liquid supply assembly 16 is used to supply cleaning fluid to the surface of wafer w, specifically the upper region of the wafer w surface located above the cleaning brush 14. The supply angle of the cleaning fluid relative to the wafer w surface is 5° to 30°. The liquid supply assembly 16 is connected to a fluid source via a delivery pipeline.

[0035] like Figure 1 As shown, the wafer support mechanism 12 is used to support and position the wafer w and drive the wafer w to rotate in a vertical plane. The wafer support mechanism 12 is fixed to the housing 11 and extends into the process chamber. The wafer w to be cleaned is supported by the wafer support mechanism 12 and rotates in a vertical plane about a horizontal axis. The rotational speed of the wafer w is 1~200 rpm, preferably 5~50 rpm.

[0036] In one embodiment, the wafer support mechanism 12 includes multiple roller assemblies. Specifically, the multiple roller assemblies may consist of two driving roller assemblies and a driven roller assembly located below the wafer w for support. The two driving roller assemblies act as a drive, using a motor to rotate the wafer w. Figure 1As shown, the angle between the two drive wheel assemblies and the center of the wafer w is less than 180°. The driven wheel assembly is positioned between the two drive wheel assemblies, serving as an auxiliary support and speed measuring component.

[0037] like Figure 1 As shown, the driving wheel assembly and the driven wheel assembly are fixed to the housing 11 and extend into the process chamber. The driving wheel assembly and the driven wheel assembly are arranged along the outer edge contour of the wafer w, with the driven wheel assembly located in the middle and the driving wheel assembly symmetrically arranged on both sides of the driven wheel assembly. The driving wheel assembly has a movable wheel for contacting the wafer. The movable wheel is connected to a drive mechanism, which drives the movable wheel to rotate. The friction between the outer edge of the wafer w and the movable wheel causes the wafer w to rotate around its axis.

[0038] Figure 2 and Figure 3 This illustration shows a roller assembly 20 for wafer cleaning according to an embodiment of the present invention. The roller assembly 20 can be either a driving roller assembly or a driven roller assembly. The composition and structure of the roller assembly 20 are described below. Figure 3 As shown, each roller assembly 20 passes through the side wall of the housing and extends into the housing. A portion of the roller assembly 20 is located inside the housing to support the wafer, while another portion is located outside the housing to connect with a drive mechanism located outside the housing or to be fixed to the housing, thus creating a gap at the point where it passes through the housing. The presence of this gap allows the roller assembly 20 to adjust its position within a certain range to better accommodate the wafer.

[0039] like Figure 3 As shown, the roller assembly 20 includes a movable wheel 21, a rotating shaft 22, a mounting base 23, and a sealing assembly 24.

[0040] The movable wheel 21 is used to abut against the wafer and drive the wafer to rotate. During cleaning, the wafer is confined in the slot of the movable wheel 21 and rotates synchronously with the movable wheel 21.

[0041] Mounting base 23 is used to fix it to the enclosure. Mounting base 23 passes through the side wall of the enclosure and extends into the enclosure. The portion of mounting base 23 outside the enclosure is connected to the enclosure via a support member. Specifically, mounting base 23 is fixed to the support member using screws. The support member and the enclosure are respectively fixed to the same base with screws. There is a gap between mounting base 23 and enclosure. The gap between mounting base 23 and enclosure is sealed by sealing assembly 24.

[0042] A rotating shaft 22 is rotatably mounted within a mounting base 23. One end of the rotating shaft 22 is connected to a movable wheel 21 to drive the movable wheel 21 to rotate. A bearing is fitted onto the rotating shaft 22. The mounting base 23 is fitted onto the outer periphery of the rotating shaft 22, and the mounting base 23 and the rotating shaft 22 are connected by a bearing. When the roller assembly 20 is a drive wheel assembly, the drive mechanism is connected to the rotating shaft 22 to drive the rotating shaft 22 to rotate.

[0043] It should be noted that the terms outer pressure ring 27, inner pressure ring 28, inward, outward, and from inside to outside mentioned below are all relative to the rotation axis 22. The one closer to the rotation axis 22 is called the inner one, and the one farther away is called the outer one. The terms up and down in the text are relative to the directions drawn in the attached diagram of the instruction manual.

[0044] like Figure 3 As shown, the sealing assembly 24 is fixed to both the mounting base 23 and the housing, sealing the gap between them. The sealing assembly 24 includes a sealing gasket 25, an outer pressure ring 27, and an inner pressure ring 28. The inner pressure ring 28 secures the sealing gasket 25 to the mounting base 23, and the outer pressure ring 27 secures the sealing gasket 25 to the housing. The inner pressure ring 28 is located inside the outer pressure ring 27. The sealing gasket 25 is annular and surrounds the mounting base 23. The sealing gasket 25 is made of an elastic material.

[0045] like Figure 2 and Figure 3 As shown, in one embodiment of the present invention, both the outer pressure ring 27 and the inner pressure ring 28 are annular. The outer pressure ring 27 has several screw holes around its circumference and is fixed to the side wall of the housing by screws. This causes the outer annular region of the sealing gasket 25 to be pressed and fixed to the side wall of the housing by the outer pressure ring 27, with the outer region of the sealing gasket 25 located between the outer pressure ring 27 and the side wall of the housing. A circular hole is formed in the center of the sealing gasket 25, and the threaded portion of the mounting base 23 passes through the circular hole of the sealing gasket 25 and then through the inner pressure ring 28. The inner region of the sealing gasket 25 is located between the inner pressure ring 28 and the mounting base 23. The threaded lock nut 26 is threadedly connected to the threaded portion of the mounting base 23. Figure 3 As shown, viewed from the inside of the housing towards the side wall of the housing, the components are, in order, a lock nut 26, an inner pressure ring 28, a sealing gasket 25, and a mounting base 23. The lock nut 26 is screwed in to press and fix the inner pressure ring 28 and the sealing gasket 25 to the front end face of the mounting base 23.

[0046] The sealing gasket 25 of the roller assembly 20 is usually made of rubber. Although some special rubbers have a certain degree of chemical resistance, the surface environment of the sealing gasket 25 is constantly alternating between water, chemical liquid, and air due to the frequent spraying of cleaning fluid in the process chamber. This makes it easy for the sealing gasket 25 material to release and shed organic contaminants into the liquid medium. The dirty water containing contaminants will contaminate the moving roller 21 and further contaminate the cleaned wafer, especially the wafer edge. In order to solve the problem of easy contamination of the moving roller 21, the present invention has made the following improvements to the sealing assembly 24.

[0047] like Figure 2 and Figure 3 As shown, in one embodiment of the present invention, the upper part of the outer pressure ring 27 has a water-blocking structure 271. During cleaning, some of the liquid flowing down from the top of the housing may come into contact with the sealing gasket 25 from the top edge and become contaminated. By providing the water-blocking structure 271 on the upper part of the outer pressure ring 27, this liquid coming from above can be blocked, preventing the contaminated liquid from re-contaminating the moving wheel 21 and affecting the wafer cleaning effect.

[0048] In one embodiment, the water-blocking structure 271 includes a water-blocking eave 272 extending outward from the outer peripheral edge of the outer pressure ring 27, and a first groove 273 formed between the water-blocking eave 272 and the housing. In one embodiment, the water-blocking eave 272 may be formed by extending the entire circumference of the outer pressure ring 27 outward. In another embodiment, the water-blocking eave 272 may be formed by extending a portion of the edge of the outer pressure ring 27 outward. The water-blocking eave 272 may extend vertically upward or inclined upward, with the inclination direction following a trend from the inside out towards the movable wheel 21. Figure 2 In the example shown, the water-retaining eaves 272 are formed by extending upwards from the outer edge of the upper half of the outer pressure ring 27 away from the housing. The water-retaining eaves 272 can block liquid coming from above. Correspondingly, a first groove 273 is formed between the water-retaining eaves 272 and the housing or between the water-retaining eaves 272 and the sealing gasket 25, which is surrounded by the outer peripheral surface of the water-retaining eaves 272 and the outer peripheral surface of the outer pressure ring 277. Since the bottom surface of the first groove 273 is an arc shape with a high center and low sides, the first groove 273 can collect the liquid blocked by the water-retaining eaves 272 and guide it downwards from both sides. That is to say, under the combined action of the water-retaining eaves 272 and the first groove 273, the contaminated liquid can flow downwards along the outer peripheral surface of the outer pressure ring 27, avoiding contamination of the moving wheel 21 and the wafer.

[0049] like Figure 2 As shown, in one embodiment, the water barrier 272 is a crescent-shaped structure that gradually narrows from high to low. In other words, the width of the water barrier 272 gradually decreases from top to bottom.

[0050] Based on the structure of the outer pressure ring 27 described above, liquid coming from the outer periphery of the roller assembly 20 will come into contact with the periphery of the sealing gasket 25. Through the first groove 273 formed between the crescent-shaped water baffle 272 at the top of the outer pressure ring 27 and the side wall of the housing, the liquid containing contaminants is guided to flow away along the outer periphery of the outer pressure ring 27 to both sides, thus preventing the liquid accumulated above the outer pressure ring 27 from being transferred from the front of the outer pressure ring 27 to the movable wheel 21, and preventing the movable wheel 21 and the wafer from being contaminated.

[0051] like Figure 2 As shown, in one embodiment, the lower part of the outer pressure ring 27 has a drainage structure 274 to facilitate drainage and prevent excessive liquid accumulation at the bottom from contaminating the adjacent movable wheel 21. Figure 2 In the example shown, the drainage structure 274 is a notch at the bottom of the outer pressure ring 27. Alternatively, in another embodiment, the drainage structure 274 can also be a groove located on the bottom surface of the outer pressure ring 27, which can also allow liquid to drain.

[0052] like Figure 3 As shown, in one embodiment, the inner circumferential surface of the outer pressure ring 27 is provided with a first guide slope 275. The first guide slope 275 is inclined from the outside to the inside along the direction close to the housing. The first guide slope 275 can guide the liquid flowing to the surface of the outer pressure ring 27 downward, so as to avoid excessive liquid accumulation on the inner circumferential surface of the outer pressure ring 27 due to capillary action and contamination of the adjacent movable wheel 21.

[0053] like Figure 2 and Figure 3 As shown, in one embodiment of the present invention, a gap is formed between the inner pressure ring 28 and the outer pressure ring 27 to accommodate the flexible deformation of the sealing gasket 25, thereby facilitating the adjustment of the position of the roller assembly 20. When the contact position between the movable wheel 21 and the wafer is adjusted, the size of the gap between the mounting base 23 and the housing changes, thereby causing the flexible deformation of the sealing gasket 25, and the size of the gap between the inner pressure ring 28 and the outer pressure ring 27 also changes accordingly.

[0054] like Figure 2 and Figure 3 As shown, in one embodiment of the present invention, the inner pressure ring 28 has a water guiding structure 281. During cleaning, the liquid flowing between the outer pressure ring 27 and the inner pressure ring 28 can be collected by the water guiding structure 281 and guided downward, preventing excessive accumulation of contaminants on the outer peripheral surface of the inner pressure ring 28 and the movable wheel 21.

[0055] like Figure 3 As shown, the water guiding structure 281 is a water guide eave 282 that extends outward from the outer peripheral edge of the inner pressure ring 28 toward the movable wheel 21. The water guide eave 282 may include an inclined portion that slopes outward toward the movable wheel 21 from the inside and a vertically extending portion. Specifically, the vertical portion extends outward from the edge of the inclined portion.

[0056] like Figure 3 As shown, in one embodiment, the water guide 282 is annular. In another embodiment, the water guide 282 may also be semi-annular or partially annular, as long as it can collect and drain the liquid when it flows into the gap between the inner pressure ring 28 and the outer pressure ring 27.

[0057] like Figure 3 As shown, in one embodiment, the outer peripheral edge of the water guide 282 is provided with a second guide slope 283. The second guide slope 283 slopes from the outside to the inside along the direction close to the housing, and the second guide slope 283 can guide the liquid flowing between the outer pressure ring 27 and the inner pressure ring 28, so as to prevent liquid from accumulating on the upper part of the outer periphery of the water guide 282 and contaminating the movable wheel 21.

[0058] Based on the structure of the inner pressure ring 28 and the outer pressure ring 27, liquids from other directions can only come into contact with the surface of the sealing gasket 25 in the process chamber by passing through the gap between the second guide slope 283 of the inner pressure ring 28 and the first guide slope 275 of the outer pressure ring 27. The liquid entering this gap is confined in the annular semi-enclosed space 284 between the outer pressure ring 27 and the inner pressure ring 28, and flows out from the drainage structure 274 along the bottom of the annular semi-enclosed space 284. For example, liquids flowing from the top of the outer pressure ring 27 to the inner circumference of the outer pressure ring 27 will enter the inner bottom surface of the annular semi-enclosed space 284 along the first guide slope 275 of the outer pressure ring 27 or the second guide slope 283 of the inner pressure ring 28. The liquid stored in this inner bottom surface is guided downward along the annular groove formed by the water guide 282 and the sealing gasket 25 in the annular semi-enclosed space 284, and then flows out from the drainage structure 274. Because the contaminants on the surface of the sealing gasket 25 did not come into contact with the lock nut 26 throughout the process, the possibility of water flowing to the movable wheel 21 through the lock nut 26 and the rotating shaft 22 was eliminated. In addition, because the first guide slope 275 and the drainage structure 274 are provided at the bottom of the outer pressure ring 27, there will be no accumulation of dirty water on the lower inner circumferential surface of the outer pressure ring 27.

[0059] Furthermore, in one embodiment, the outer surface of the movable wheel 21 is provided with a hydrophobic coating or a superhydrophobic coating, such as polytetrafluoroethylene, perfluoroethylene propylene, etc., so that the surface of the movable wheel 21 is not easily contaminated with liquid and contaminants are avoided from remaining on the surface of the movable wheel 21.

[0060] In summary, the outer pressure ring 27 and the inner pressure ring 28 work together to guide the liquid flowing on the sealing gasket 25 to avoid the lock nut 26, thereby cutting off the path of the liquid that comes into contact with and is contaminated by the sealing gasket 25 to the moving wheel 21. This blocks the path of contaminants between the contaminated components and the wafer to be cleaned, thus solving the problem of random contamination of the wafer by the dirty water from the sealing gasket 25 when the wafer is vertically brushed. This significantly improves the cleanliness near the edge of the wafer and greatly enhances the effectiveness and stability of the cleaning process.

[0061] The accompanying drawings in this specification are schematic diagrams used to illustrate the concept of the invention and to schematically show the shapes of the various parts and their interrelationships. It should be understood that, in order to clearly show the structure of the various components of the embodiments of the invention, the drawings are not drawn to the same scale, and the same reference numerals are used to indicate the same parts in the drawings.

[0062] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0063] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A roller assembly, characterized in that, Coupled to the housing for wafer cleaning, it includes casters, a rotating shaft, a mounting base, and a sealing assembly; The sealing components are fixed to the mounting base and the housing respectively, and are used to seal the gap between the mounting base and the housing. The sealing assembly includes a sealing gasket, an outer pressure ring, and an inner pressure ring. The inner pressure ring secures the sealing gasket to the mounting base, and the outer pressure ring secures the sealing gasket to the housing. The inner pressure ring is located inside the outer pressure ring. A gap is formed between the inner pressure ring and the outer pressure ring. The inner circumferential surface of the outer pressure ring is provided with a first guide slope. The inner pressure ring has a water guide eave extending outward from its outer circumferential edge toward the movable wheel as a water guide structure. The outer circumferential edge of the water guide eave is provided with a second guide slope. The lower part of the outer pressure ring has a drainage structure.

2. The roller assembly as claimed in claim 1, characterized in that, The upper part of the outer pressure ring has a water-blocking structure.

3. The roller assembly as claimed in claim 2, characterized in that, The water-blocking structure includes a water-blocking eave extending outward from the outer peripheral edge of the outer pressure ring and a first groove formed between the water-blocking eave and the box body.

4. The roller assembly as claimed in claim 3, characterized in that, The water-retaining eaves are crescent-shaped structures that gradually narrow from high to low.

5. The roller assembly as claimed in claim 1, characterized in that, The drainage structure is a notch at the bottom of the outer pressure ring.

6. The roller assembly as claimed in claim 1, characterized in that, The water guide eaves are ring-shaped.

7. The roller assembly as claimed in any one of claims 1 to 6, characterized in that, The rotating shaft is rotatably mounted in the mounting base, and one end of the rotating shaft is connected to a movable wheel.

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